Plenum type crystal growth process

Abstract

Crystals are grown in a tank which is divided by a baffle into a crystal growth region above the baffle and a plenum region below the baffle. A turbine blade or stirring wheel is positioned in a turbine tube which extends through the baffle to generate a flow of solution from the crystal growing region to the plenum region. The solution is pressurized as it flows into the plenum region. The pressurized solution flows back to the crystal growing region through return flow tubes extending through the baffle. Growing crystals are positioned near the ends of the return flow tubes to receive a direct flow of solution.

I claim: 
     
       1. A method of growing a crystal, comprising: dividing a crystal growth chamber into an upper crystal growing region and a lower plenum region by means of a stationary horizontal baffle extending across the chamber;   providing a turbine tube through the baffle between the crystal growing region and plenum region;   providing at least one return flow tube through the baffle between the crystals growing region and plenum region, each return flow tube having a diameter less than the turbine flow tube;   filling the crystal growing region and plenum region with crystal growing solution;   providing flow generating means in the turbine tube;   continuously drawing crystal growing solution from the crystal growing region through the turbine tube into the plenum region by actuating the flow generating means in the turbine tube to pressurize crystal growing solution in the plenum region and to produce a continuously recirculating flow of crystal growing solution from the pressurized plenum region through the at least one return flow tube to the crystal growing region;   positioning a growing crystal in the crystal growing region at each return flow tube so that the recirculating crystal growing solution flows directly into the crystal.   
     
     
       2. The method of claim 1 further comprising maintaining the crystal growing solution in the crystal growing region and plenum region at a substantially constant temperature. 
     
     
       3. The method of claim 1 comprising positioning the baffle at a height, forming the turbine tube and return flow tube of diameters, and flowing solution from the crystal growing region to the plenum region at a rate to control pressure increase in the plenum region and control the continuously recirculating flow of crystal growing solution from the plenum region to the crystal growing region. 
     
     
       4. The method of claim 2 further comprising maintaining the crystal growing solution at about its saturation temperature.